1. Field of the Invention
This invention relates to skis used on snowmobiles and similar vehicles and more particularly relates to wear bars attached to a bottom surface of the ski for turning on ice and snow.
2. Description of the Related Arts
Technology has made it possible to travel off-road during winter, even in very remote areas. Current machines for traveling over snow, such as snowmobiles, for example, provide the ability to travel swiftly and safely in back-country locations where the terrain is quite rugged. Winter sports industries such as recreational vehicle sales and rentals and tourism are growing rapidly as a consequence of this new technology. Industry and rescue operations are also benefiting greatly.
Snow machines continue to be refined and improved. For instance, in the case of snowmobiles, improved performance and reliability allows operators to travel swiftly, safely, and comfortably into secluded regions otherwise inaccessible in winter and in some cases in summer also. Other technological advances, such as increased traction, power, and weight reduction are allowing snowmobiles to be operated in snow depths and terrain previously thought impossible.
The snowmobile is a light and agile tracked snow machine that is intended primarily for recreational operation by one or two persons. The small size, lightness, and high power output of these machines makes them highly responsive to shifts in weight and other operator inputs. Using tracks with large lugs and high powered engines, these machines can go faster over trails and deeper in rugged terrain than larger snow machines such as the dual-tracked, multiple passenger vehicles currently available. The ruggedness of snowmobiles allows operators to travel over the snow safely at speeds impossible to match by wheeled vehicles in summer and to travel directly to any desired point by “as-the-crow-flies” navigation.
Typically, a snowmobile comprises an elongated rubberized looped track of about 10 or more feet in length, of which three to six feet contact the snow. The snowmobile is driven by a two-stroke or four-stroke engine, and the power is applied to the track with the use of a centrifugal clutch. Unlike dual-tracked snow machines, the snowmobile track does not extend entirely to the front of a snowmobile. Instead, the front of the machine rests on one or two specially adapted skis, such as the ski 100 of FIG. 1. The skis are attached to the steering mechanism of the snowmobile which may be provided with suspension components to handle bumps. With the use of the handle bars, the operator is able to alter the facing of the skis. Turning the skis in a selected direction generally causes the snowmobile to follow the selected direction of travel of the skis and turn in that direction.
Conventional snowmobile skis are designed under the notion that to provide the highest degree of speed and flotation, the ski must be smooth and relatively flat. Thus, conventional snowmobile skis are typically smooth and flat. A single shallow keel is often tyically provided extending along the center of the ski to exert a lateral shear force against the snow when the ski is turned, forcing the ski to adhere to an intended direction of travel. Alternatively, a ski with dual keels such as the ski 100 of FIG. 1 has been developed to improve flotation, safety, and turning.
Wear bars 118 are typically placed at the bottom of the keels of the snowmobile skis, generally at the bottom of the keels as shown in FIG. 1, though not necessarily so. One or more wear bars 118 may be located on the bottom of each ski. The wear bars 118 enhance the turning ability of the ski 100, especially on hard packed snow and ice. The wear bars are also typically replaceable, allowing a low cost part to be replaced periodically when wear occurs, rather than the entire ski.
Even with the use of keels and wear bars, conventional snow machine skis may still experience lateral slippage on hard packed surfaces. The sliding of the conventional skis in the original direction of travel is termed “pushing.” In order to overcome this behavior, hardened inserts have been coupled to the wear bars 118. The inserts, generally positioned towards the rear of the wear bar 118, provide additional shear force during a turn. In some wear bar designs, hardened inserts 202, as seen with reference to FIG. 2, are generally configured extending outward from approximately the bottom of the wear bar 118 and are disposed at the rear of the wear bar 118. Unfortunately, on hard-packed surfaces, this arrangement causes a situation wherein the wear bar 118 may not be in contact fully with a hard packed surface, as illustrated in FIG. 2. In such a situation, the ski tips to the front, causing the wear bar and consequently the hardened inserts 204 to contact the underlying surface (e.g., hardened snow or ice) at an angle. This can cause the snowmobile to track improperly on a hard-packed surface, and can cause the wear bar 118 to wear unevenly.
As technological barriers are being overcome, certain limitations of current snow machines have come glaringly to light. To fully utilize current technological benefits, snowmobiles must be provided with increased flotation ability, steering ability, and tracking capability. Until these needs are met, much terrain will remain impassible or at least dangerous to the operators of snow machines.
As a result of the above discussion, it should be readily apparent that if a ski could be used to provide high floatation in powder snow and also provide improved steering on packed and groomed surfaces, the ski would be a great improvement in the art, complementing the technological advances already made. Such a ski would provide increased winter access to rugged terrain, greater enjoyment to consumers, and greater safety for those traveling off-road in winter.